Hi Edgar,
I just view the photos, really good photos actually, alot of photographers would have much difficulty capturing fireworks as each firework display intensity is never the same.. so, it is difficult to gauge. There are techniques like covering the lens with a cloth to prevent overexposures and shooting in Bulb mode etc... Do take more photos.. D300s is fantastic in portraiture.
Oh, by the way Flickr is another good website to store your online photos, free too!
